1. Technical Field of the Invention
This invention relates to client/server and similar systems, such as in a TCP/IP or internet or intranet environment. In particular, this invention relates to the use of encoded tokens for synchronization of connectionless applications between a server and a client across a network.
2. Background Art
Software applications sometimes require a way to synchronize communications between a client and server. In particular, Internet type applications which are subject to frequent connect/disconnect cycles between client and server applications (and are thus characterized as "connectionless") sometimes need to insure both client and server applications are "in sync" in order to allow some types of transaction processing to continue.
For example, many terminal emulation programs communicate with AS/400 computers using a 5250 architecture protocol. The 5250 architecture has strict protocol requirements regarding how and when data streams are transmitted and received. Terminal emulators function well because, with these programs, the client and server never disconnect and thus know the state or synchrony of each other.
Many new types of Internet servers are being developed which attempt to replace terminal emulators and communicate using, for example, the 5250 architecture protocol. However, since Internet servers are subject to connect/disconnect cycles, a mechanism is needed to insure the client and/or server program can check and see if the other side is in the correct state or "synchronized."
It is an object of the invention to provide a method and apparatus for synchronizing communications between a client and server.
It is a further object of the invention to provide such synchronization while allowing the client and server to disconnect between communication cycles.
It is a further object of the invention to use CRC hash encoding or other simple encoding techniques to provide synchronization tokens for connectionless communications.